For many of us, the computer is the symbol of our hypermodernity, the image of how vastly we differ--culturally, economically, socially and politically--from past generations. And many of us think of our hypermodernity as a phenomenon of the 1990s, when PCs became fixtures in our homes, and the Internet became one of our primary means of communicating, working, shopping, playing and even procrastinating.

But the idea of the computer is old indeed, traceable to a largely forgotten Victorian inventor named Charles Babbage. Doron Swade's "The Difference Engine: Charles Babbage and the Quest to Build the First Computer" tells the story of Babbage's lifelong dedication to the idea of the computer, from the moment in 1821 when he exclaimed that mathematics ought to be powered by steam, until his death half a century later, a slightly addled old man still hard at work on his eternally evolving designs.

Swade's book also tells the story of his own dedication to Babbage's vision: The final third of "The Difference Engine" describes how, as curator of computing at London's Science Museum, Swade finally finished the work Babbage began over 150 years ago.

A classic curmudgeonly polymath who was known--with good reason--as "The Irascible Genius," Babbage was an inveterate, obsessive thinker, a mathematician with a penchant for engineering that led him, over the course of his long and colorful life, to invent such varied items as the ophthalmoscope, the cowcatcher found on the fronts of locomotives, the black-box recorder (for trains), a submarine automated by compressed air, a seismograph for measuring earthquakes, a "coronagraph" for generating artificial eclipses, a pen that drew dotted lines (for mapmaking), ergonomic paper (green ink on green paper, Babbage found, was easiest on the eyes), and a pair of shoes designed to let the wearer walk on water (Babbage nearly drowned when testing them, thus establishing that his considerable mental powers did not extend to working miracles).